This invention relates to a closed type alkaline storage battery having a diaphragm type safety valve that has a hat-shaped terminal closure with a piercing needle and a diaphragm positioned below the piercing needle. The needle is fixed by caulking, to the peripheral edge of the closure, and gas pressure in the storage battery is extraodinarily heightened, the diaphragm is punctured by the piercing needle and the inner gas of the storage battery is discharged to the external open air.
In this kind of storage battery, utilizing the hat-shaped closure as a terminal, there has hitherto been adopted either, an arrangement where a leading wire extends from one polarity electrode of a battery element and comprises a set of anode and cathode electrode plates contained in a container. The wire is led out to the exterior by being passed through the inside of the caulked portion of the closure and the outer end thereof and is connected to the outside surface of the closure.
In an alternative arrangement the leading wire is connected by spot welding or the like through the diaphragm to the inside surface of the closure. Consequently, in the former case, it is defective in that sufficient airtightness by the caulking cannot be obtained along and around the passing portion of the leading wire passing through the caulked portion. As a result, a battery is produced which is insufficient in airtightness. In the latter case, it is defective similar to the above case where a portion insufficient in airtightness results along and around the leading wire because the leading wire connected to the inside of the closure is positioned in the caulked portion. These defects cannot be avoided especially when the storage battery is small in size.